Writing by the Scientist :Origin of species by means of natural selection(1859) ; Descent of man (1871)

Born into a wealthy family, Darwin grew up amidst a life of wealth and comfort . His father was a doctor and had similar aspirations for him. It was no surprise therefore that Darwin first studied medicine at Edinburgh. However, it soon became clear to the family, and particularly to young Charles, that he was not cut out for a medical career. He then went to Cambridge to train to become a clergyman . While at Cambridge, Darwin befriended a biology professor John Stevens Henslow, and his interest in zoology and geography grew. An unforeseen opportunity precluded Darwin's plan of becoming a clergyman. He was invited on board the ship, H.M.S. Beagle as a gentleman companion to the captain.
The round-the-world journey on H.M.S.Beagle lasted almost five years. Darwin spent most of these years investigating the geology and life of the lands he visited, especially South America, the Galapagos islands, and Pacific coral reefs. This journey triggered in him, an interest in evolution of life on earth, the diversity in plant and animal life, and how they survived.
Upon his return to England in 1836, Darwin tried to solve the riddles of these observations and the puzzle of how species evolve. He began to develop the theory of evolution that was to make him famous.
Darwin proposed that all life on earth developed gradually over millions of years from a few common ancestors. In other words, the numerous species alive today arose from a single original life form. They developed new characteristics to adjust to different conditions and environments. Those that could not survive perished.
He called this process of evolution - natural selection. All life, he said, is a continuous struggle in which only the fittest can survive. In other words, in the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.
Darwin was the first of the evolutionary biologists. Until then, people believed that the world they lived in, was the same as what God had created thousands of years ago. Darwin’s theories met with fierce opposition, and even though his theories have been questioned and debated upon, “Darwinism” as his theories are called, remain the first ever documentation on how such a variety of species of plants and animals evolved.
Darwin continued to write and publish his works on biology throughout his life. He lived with his wife and children at their home in the village of Downe, fifteen miles from London. In the later years, Darwin was plagued by fatigue and intestinal sickness. He died on 19 April, 1882, and lies buried in Westminster Abbey.